def main():
    X = int(input())
    if 30 <= X:
        print("Yes")
    else:
        print("No")


if __name__ == '__main__':
    main() def main():
    X = int(input())
    if 30 <= X:
        print("Yes")
    else:
        print("No") main X = int(input()) X int(input()) int input() input if 30 <= X:
        print("Yes")
    else:
        print("No") 30 <= X 30 X print("Yes") print "Yes" print("No") print "No" if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    X = int(input())
    if 30 <= X:
        print("Yes")
    else:
        print("No") def main():
    X = int(input())
    if 30 <= X:
        print("Yes")
    else:
        print("No") main
def main():
    X = int(input())
    if 30 <= X:
        print("Yes")
    else:
        print("No")


if __name__ == '__main__':
    main()
